Refrigerated display cabinet



3x1/vamo@ 2, i430 w. A. EL'LSWORTH ET AL REFIGERATED DISPLAY CABINET Filed June` 13, 1940 aan DeC- 21, 1943- 'W. A. ELLSWORTH ET Al. 2,337,039

REFRIGERATED DISPLAY CABINET Filed June 13, 1940 2 Sheets-Sheet 2 FIG.

In N

WALTER A. ELLSWORTH DONALD F. SWANSON refrigerator.

Patented Dec. 21, 1943 N UNITED sm-'rias PArENr oFFlcE 1'" L .l l V`Waltveiw-.Ellsworth and DonaldfFf Swanson; :t

. o St. Paul, kl`VI`in1,1.,`a.ssignors tomSeegex` Refrig- Y n eratorlCompanygSt. Pauly, Minn:I acorporationf. Application June 13, 194.0,sr'ii 15115340.32, i.

` j eoiails. :.(Cl. 6ft- 102) Our invention relates vto an improvement ina forced convection system of refrigeration, where# in it is'desired to provide a' manner votcooling a. refrigerator which differs frornlthe'natural air circulation system. 1 l

Refrigerators have lpreviouslyr been provided with fans by means of`which-cooled-air may be forced into space requiring refrigeration.v These former systems have usually had certaindisadvantages. Most of theseA constructions have been provided with a fan to blow relatively Warm 4air over a cooling coil and into the space lto be refrig- Z erated. Other constructions have embodied ba'files built into the refrigerator` to conduct the air a predetermined pathwithin theI body of the It is an object of the present invention to provide a refrigerator construction in which the' displaypans or trays act as baffles for the air; these wwwand thus are directly cooled. This differs mate-f rially from the usual constructionrin which baffles are built beneath the display'pans; forsuch baliies limit the direct contact of the cooled air with the pans. In the second place, the refrigerator is lighter, more efficient to operate, and` cheaper to construct. A better and more complete circulation of `cooled air is provided throughout the refrigerator with fewer parts, so that the cooling unitrnay' maintain a more even temperature throughout the entire-cabinet.

It is another object of the present invention to provide a means forwithdrawing the warm air from the topof v"the refrigerator. The cooling means for a refrigerator isfusually positionedat the top of therefrigerator, andthe `air cooled thereby tends to drop downwardly, causing av cirulation of the warmer air upwardly.4 Inthe :present system, the warm air is withdrawn from the top of the refrigerator, conducted downwardlyto the cooling coils, and is forced transversely across the bottom of the box, the cold air forcing the warmer air upwardly into position to beA again removed and conducted over `the *cooling coils again. l

It is a further featureof our inventionto pro-` vide a means of drawing air over the cooling coils, rather than blowing air over the same. The vair blown by the fanmight readilybe forced between adjacent portions of the.' coils without actually contacting the saine. By positioning the coils in" the inlet to the fan, however, and b'y providing a :coil vwhich `is largerthan thejfan, the vairis fidrawn fromall portions of the coil, `decreasing vthe speed of ltravel ofair through any one portion :ofthe coil, lso thatV the air may be cooledrto. a `greater extent-,bythe coils as' it venters the fan.

p These andgother4 objectsV and novel features'of vour invention :willbe more clearly and fully set Figure 3 is forth` in the follovwingspecication yand clainis.

`cation:

l.inthe drawings forming a part'of our specifi- Ourrelrigerator A` maybe of an'y desiredout- L ward conformationpand is shown having a base lllfendwalls il and l2, a'ito'p I3, anda rear wall M., The frontwallof the refrigerator, which in such a construction isi provided with one ormore display windows, being a common `type of construction.A 'I'he walls'are preferably formed with outer covering members l5, and inner lining m'embers lli, withinsulation, il of` any desired type Y' therebetween.

of theupper portion of the cabinet. Two large v doors 2U areY shown inthe rear wall l4,'through which lmaterials may ber inserted'into, vor witndrawn from, the lower storage portion of the cabinet.`

Extending` from the rear'wall M tothe front wall of the cabinet, dividing theupper andlower portions of kthe cabinet, we provide a wire shelf 2l which, in the `form shown, slopes downwardly `at, a gentle angle from therear` -wallul4 to the v front wall. A; series of pans 22 are positioned on the shelf 2|, arranged in spaced relation. 'These pans support products 4to be displayed or to be contained withinxthe refrigerator, and cover the greatestportion of the area of the shelfZI.v Air v may `iow through the spaces between the pans 22- and-into theupper portion of the cabinet.

. Thus in addition to providing a support for the products to be displayed, the pans 22 act as bafator body.

Adjacent one end I l of the refrigerator cabinet, we provide a vertically extending duct 23 formed by a vertical partition wall 24. This wall 24 is provided with openings 25 therethrough in the upper portion thereof, through which warm air from the upper portion of the cabinet above the pans 22 may be drawn. A cooling coil 26 is mounted lwithin the lower portion of the duct 23, which coil is refrigerated in any suitable manner. In usual practice, a compressor unit 21, illustrated in the wiring diagram, acts to cool a cooling medium which Iiows through the coils 2B to refrigerate the same. The compressor unit may be located either within the lower storage portion 29 of the refrigerator beneath the level of the pans 22, or may be outside of the refrigerator cabinet. The cooling coil 26 is preferably of the direct expansion type with built-in heat exchanger; ancl the coil is preferably substantially larger than the blower fan to allow more uniform cooling of the air.

Afan 30 driven by a. motor 3|, draws air cooled by the coil 26 into the lower storage portion 29 of the refrigerator A. This construction has been found more effective than arrangements wherein the fan blows air forcefully over a cooling coil. The air leaving the fan is directed in somewhat of a straight path, and if the coil were in the path of air' leaving the fan, some of the air might readily flow between the coils without touching the same.' By drawing the air through the coil, the air is drawn from all directions through all parts of the coil, so that the movement of the air through any one portion of the coil is slower than it could otherwise be. Thus the air is cooled more effectively, and the entire coil, rather than a small portion of the entire coil, is used to a good advantage.` If air were forced by the same fan through a coil of the size illustrated, only a portion of the coil would be used most efficiently.'

The wiring diagram which can be used with the system illustrated in Figure 1 is shown in Figure 2 of the drawings, Line wires 32 and 33 supply the'current for operating the refrigerator and fan. The line wire 32 is connected by conductors 34 and 35 tothe compressor motor 21. The other terminal of the motor 21 is connected by conductors 36 and 31 to the thermostat 39 which is connected by connector 40 to the line wire 33, completing the circuit.

A relay coil 4| is connected in parallel with the motor 21. The line -wire 32 is connected by conductors 34 and 42 to one terminal of the relay coil 4|. The other terminal of the c oil 4| is connected through conductors 43, 31, thermostat 39. and conductor 40 to the line wire 33, completing the circuit. Thus when the compressor motor 21 is in operation, the coil 4| is energized.

The line wire 32 is connected to a conductor 44 lea-ding through the resistance coil 45 to conductor 46 connected to one terminal of the fan motor 3|. The other terminal of the motor 3| is connected by conductor 41 to the line wire 33. completing the circuit.

The conductor 45 is connected by conductor 49 to the armature 50 of the relay coil 4|; while the wire 44 is connected by the conductor 5| to a contact 52. When the coil 4| is energized, the armature D connects the conductor 49 with the contact 52, thus shorting out the resistance 45 and increasing the voltage to the motor 3|. When the coil 4| is not energized, the circuit between the contact 52 and the armature 50 is broken, and the current to the fan must pass through the resistance 45. thus cutting down the speed of the fan motor 3|.

In operation, the thermostat 39 controls thc compressor motor 2T. When the thermostat callsI for a lower temperature within the refrigerator, the circuit is closed through the thermostat to the motor 21, starting the compressor into operation. Simultaneously, the coil 4| is energized, shorting the resistance coil and closing a direct circuit to the motor 3| of the fan 3|). The fan speed increases, drawing a greater amount ol warm air from the top of the refrigerator' down through the duct 23 and over the coil 26A This cooled air is then forced by the fan 3B into thc lower portion 29 of the refrigerator. When the thermostat 39 cuts off the compressor motor 21'4 the circuit to the coil 4| is broken. the armature drops, breaking the short circuit around the resistance 45, decreasing the speed of the fan 38.

The cooled air directly contacts the pans 22, and these pans form ducts for the upward passage of air. Because of the limited space provided for the upward passage of the cooled air, the temperature throughout the storage portion of the'refrigerator body is equalized, providing a uniform temperature. from end to end of the body. The warm air which naturally collects at the top of the cabinet is drawn oi by the fan. and recooled by passingy through the cooling coil E.

In accordance with the patent statutes. we have described the principles of construction and operation of our forced convection system of refrigeration, and while we have endeavored to set yforth thebest embodiment thereof. we desire to have it understood that this is only illustrative of a means of carrying out our invention, and that obvious changes may be made within the scope of the following claims without departing from the spirit of our invention. f

1. A refrigerated display cabinet, comprising a closed chamber having display windows in its front, a fixed perforated horizontal partition dividing the chamber into elongated top and bottom portions which are open and unobstructed throughout substantially their'eniire adjacent lengths, display trays supported on'` said ipartition so as to close passage of air through the same except through spaces about the margins yof said trays, cooling means located in tha-bottom portion adjacent an end thereof and hav ing air duct communication at said end from the upper portion and ,to the lower portion'of the cabinet chamber, and means for drawing air from the upper portion of said chamber andforcing it into the lower portion of said chamber after passing through the vcooling means, lwhereby the cooled air will be put under substantially uniform pressure throughout the length `of said lower portion, which pressure will cause the air to circulate about the display trays and to more troni the lower portion uniformly to all parts of the upper portion through the spaces about said trays.

2. A refrigeratecldisplay cabinet. comprising a closed chamber having display windows in "t: front. a iixed horizontal partition dividing the chamber into elongated top and bottom pomo-os which are open and unobstructed throughout. substantially their entire adjacent ltngtliS display trays supported on said partition, said partition being formed to provide means for permitting air to circulate from the bottom portion to the top portion of the chamber, a. vertical partition forming a vertical chamber across one end of both portions of the closed chamber and having openings into the upper part of the tcp f throughout the length of said lower portion, which pressure will cause the air to circulate aboutthe display trays and to move from the lower portion uniformly to all parts of the upper portion through the spaces about said trays.

WALTER A. ELLSWORTH. DONALD F. SWANSON.- 

